About 6 calories each or so (if you mean M&M the chocolate candy). If you meant millimeter, there is no relationship between calories and millimeters.
260 calories
According to one online resource, one m&m has about 4.5 calories, 0.2g fat and 0.6g carbs.
There are 203 calories in 203 calories.
6450 mm
100 mm
3,000 mm
153 mm
180 mm
8500 mm
304.8 mm
135 mm.
760 mm